The present invention relates to the starting of aircraft engines, particularly jet engines and to the driving of on-board, auxiliary power generating equipment. The invention is developed particularly in relation to VTOL type aircraft, but is not restricted thereto.
It is known to provide an auxiliary gas turbine in an aircraft for purposes of starting the main engines. Furthermore, such a gas turbine can be used to drive additional equipment such as hydraulic pump, electric generator and fuel pump. The usual manner of driving such auxiliary power equipment, however, is to connect them to one of the engine shafts.
It was found however, that the disposition of an equipment carrier right at one of the engines and connecting it thereto is a disadvantageous arrangement because the equipment is not readily accessible for maintenance. Moreover, arranging the several pieces of auxiliary equipment right at the engine may lead to compromises in the aerodynamic design of the engine casing precluding optimization. Also, a gear permitting speed control has to be used here because for example the a.c. frequency of the generator must be maintained independently from the engine speed.